Wes Thomas' first-half equaliser saw Oxford secure a 1-1 draw at Southend.
The Shrimpers took the lead in the 19th minute when a fine left-wing cross from Stephen McLaughlin was tapped home by Simon Cox from close range.
But the U's hit back just three minutes later with Thomas brushing aside a weak challenge from Southend skipper Anton Ferdinand to score.
The Shrimpers came close to going back in front in the 41st minute when Josh Wright sent a 20-yard volley against the crossbar but the U's Josh Ruffels then saw a similar effort bounce back off the woodwork just before half-time.
After the break, Thomas fired wide of the right post before former Southend midfielder Jack Payne saw his goalbound effort blocked by Jason Demetriou.
James Henry then also sent a 20 yard shot inches wide of the target for the U's before Southend pushed forward with Wright firing wide of the right post from six yards while Michael Turner and Nile Ranger both had efforts ruled out for offside.